1. Field of the Invention
The present invention relates to an improved multipolar circuit breaker used for a molded-case circuit breaker or an earth-leakage circuit breaker.
2. Description of Prior Art
In the case of a multipolar circuit breaker having a plurality of poles to be used to break a plurality of circuits, the pole of each circuit is independently provided with a mechanical section such as a cradle or a tripping section and thus, a structure must be used in which, when the tripping section of the pole of any circuit operates, tripping sections of poles of other circuits operate so that the circuits can be broken.
Therefore, conventionally, as shown in FIGS. 8 and 9, bottoms of trigger plates 1 of tripping sections of poles are connected to each other by a trigger joint 2 so that, when the trigger plate 1 of any pole is moved and a cradle 3 is tripped due to an overcurrent or the like, tripping is performed also in other poles.
However, the engagement amount between the trigger plate 1 and the cradle 3 slightly fluctuates every pole, or even if tripping is performed in one pole, it may not be performed in other poles due to a slight backlash between the trigger plate 1 and the trigger joint 2. Therefore, a severe factory-adjustment must be performed to prevent the above problem.
Problems to be Solved by the Invention
The present invention is made to solve the above conventional problem and its object is to provide a multipolar circuit breaker which makes it possible to securely operate tripping sections of poles of other circuits when the tripping section of the pole of any circuit operates.